Physico-chemical investigations and thermal degradation studies of 4-ethylpiperazine-1-carbodithioic acid complexes of copper(II)

Synthesis of copper(II) carbodithioates, viz.[Cu(4-EtPipzcdtH)2]Xn (4-EtPipzcdtH = 4-ethylpiperazine-1-carbodithioic acid, X = Cl, ClO4, NO3 and CH3COO when n = 2; X = SO4 when n = 1), has been carried out. These have been investigated by FT-IR, UV–Visible spectral and room temperature magnetic (1.59–1.72 B.M.) studies. 1H NMR and ESMS of [Cu(4-EtPipzcdtH)2](ClO4)2 and [Cu(4-EtPipzcdtH)2]Cl2 further supported their formation. Based on characterization techniques chelating bidentate mode of coordination of ligand, 4-EtPipzcdtH with four coordination around copper(II) was proposed. Copper(II) carbodithioates with Cl, ClO4, NO3 and CH3COO as counter anions exhibited 1:2 electrolytic behaviour, while 1:1 electrolytic behaviour was observed for complex with SO4 as counter anion. Cyclic voltammetry study conducted on complexes, viz. [Cu(4-EtPipzcdtH)2]Xn (X = Cl, ClO4, NO3 when n = 2; X = SO4 when n = 1) revealed redox process due to CuII/CuIII couple. Complexes were also studied using non-isothermal techniques (TG/DSC). The complexes [Cu(4-EtPipzcdtH)2]X2 (X = ClO4, NO3) showed oxidative thermal decomposition behaviour.